Fix ShapeResult::offsetForPosition for RTL scripts

Source/platform/fonts/shaping/HarfBuzzShaper.cpp

Index: Source/platform/fonts/shaping/HarfBuzzShaper.cpp
diff --git a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
index 981a642c5be9cb3e9214488357af0c6f49528679..8e08064d0cf049dbd92b8b1f8edd7a22f26d3aee 100644
--- a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
+++ b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
@@ -452,7 +452,8 @@ int ShapeResult::offsetForPosition(Vector<RefPtr<ShapeResult>>& results,
     unsigned totalOffset;
     if (run.rtl()) {
         totalOffset = run.length();
-        for (auto& wordResult : results) {
+        for (unsigned i = results.size(); i; --i) {
+            const RefPtr<ShapeResult>& wordResult = results[i - 1];
             if (!wordResult)
                 continue;
             totalOffset -= wordResult->numCharacters();